Okay, that site, when following its instructions, really messed me up bad. I'm in a real bad state.

It said I'd get a "1015" error or some such, and to recover from that, I'd need to run something called IRESTORE to ubrick the phone.

Well, I got an "irestore" package, linked from that very web site. And when I installed it (edit: Specifically when I installed the LIBUSB package it came with), it made all my USB ports stop working and made the computer BSOD at boot time, so now my computer is in an infinite reboot loop.

Doing a system restore now. Arg.